The cruise liner Costa Concordia ran aground off the island of Giglio, Italy, in January 2012.

Andreas SolaroAFP/Getty Images

It's been a rough voyage for the cruise-line industry in the past few years.

The engine room fire, power outage and ensuing problems aboard the stricken Carnival Triumph in recent days are far from the first recent major problem aboard a cruise ship. In 2010, for example, a similar fire, with a similar outcome, occurred aboard the Carnival Splendor. A year ago, there was the Costa Concordia disaster. And just this week, a lifeboat accident aboard a Thomson Cruises ship killed five crew members and caused the company to cancel the cruise and fly the passengers back home.

Ross Klein, a professor at Memorial University of Newfoundland who tracks cruise-line mishaps on his website CruiseJunkie.com, makes a direct connection between the growth of the cruise industry and the spate of problems. "I think we are seeing more incidents because there are more ships," he says.

Maximum Capacity

Ships run by the Carnival Corp. have had a number of the problems in recent years, a fact that Mike Driscoll, editor at Cruise Week, notes is likely due to the company's "near oligopoly" in the industry — besides flagship brand Carnival, it also owns Costa Cruises, Princess Cruises, Holland America, Cunard and P&O, among others.

But Driscoll says another issue could be the sheer size of the vessels. They've become much bigger since the first of the "floating playground" style luxury ships made their appearance circa 1970.

"I think there is a general feeling that these ships have reached about the maximum size," he says.

Take the 1971-built Pacific Princess, made famous on television as the "Love Boat." It was just over 500 feet long and 20,000 gross tons. Compare that with the 1,187-foot, 225,000-ton Allure of the Seas, launched three years ago by Royal Caribbean International.

"Allure of the Seas and [sister ship] Oasis of the Seas, I think that's about the biggest you're going to get," Driscoll says. "I think that safety is an issue. There are so many passengers on these floating cities. What happens when things go wrong?"

Sizing Up Safety

Jay Herring, a former senior officer at Carnival and author of the book The Truth about Cruise Ships, told NPR's Greg Allen that with more than 3,000 passengers — many of them children and elderly — unless the ship is sinking, evacuating them over open water is just not possible.

"So imagine you have this little bitty boat, bobbing up and down, and you're trying to transfer passengers from a ship that's essentially stationary, walking across a gangway. It's just so dangerous," he says.

In short, with bigger ships come bigger and more expensive potential safety headaches. Driscoll says the wreck of the Costa Concordia off Tuscany in January 2012 — in which getting passengers off the ship was part of the problem — was a key event that "drove up" the cost of protection and indemnity insurance, though the industry won't say by how much.

Carnival CEO Gerry Cahill said this week that the company's priority was to ensure the safety of its guests. Bud Darr, vice president of technical and regulatory affairs at the Cruise Line Industry Association, says "the industry has no bigger commitment than to safety."

A Shift In The Wind?

Still, Driscoll is quick to note that the incident with the Carnival Triumph is likely to be just a blip on the radar for an industry that has seen phenomenal growth over the years.

"It always seems in the first week that people say, 'Oh my gosh,' but then they think, 'But this won't happen to me' and the normal patterns resume," he says.

Spencer-Brown, who spoke with NPR's Allen, says the site's forums have been getting a lot of traffic about the Triumph incident. "People are saying, 'I just don't have confidence in Carnival anymore,' " she says. "It has nothing to do with reality, but it has a lot to do with perceptions."

Former Carnival officer Walt Nadolny says one of the cruise line's problems this week has been the extensive media coverage, which he thinks at times has verged on hysteria.

"Everybody thinks they're going to die on the ship and I'm just shaking my head," he tells Allen.

"Agreed that they are in discomfort, [that] they don't have air conditioning. It's hot," he says, but it's made worse by the media "then grabbing that bone and saying, 'Let's blow it out of proportion.' "